A computer network is a collection of interconnected computing devices that exchange data and share resources. In a packet-based network, such as the Internet, the computing devices communicate data by dividing the data into small blocks called packets. The packets are individually routed across the network from a source device to a destination device. The destination device extracts the data from the packets and assembles the data into its original form. Dividing the data into packets enables the source device to resend only those individual packets that may be lost during transmission.
To route the packets through the computer network, each network device may be assigned an address that uniquely identifies each of the requesting network devices. Each packet may then include a source address uniquely identifying the network device that originated the packet and a destination address uniquely identifying the network device to which the packet is destined. Intermediate devices, referred to as routers, may route the packets to the destination device based on the destination address included within the packet.
Typically, each network device, upon attempting to access the network, may request configuration information that includes an Internet Protocol (IP) address in accordance with a Dynamic Host Configuration Protocol (DHCP). For example, a subscriber device (e.g., a cable modem, a digital television setup box, a Digital Subscriber Line (DSL) modem) may request a layer three IP network address by issuing a DHCP request. A DHCP server that maintains an IP address space may receive this request, reserve an IP address with the IP address space, assign the IP address to the requesting network device, and forward a response back to the network device assigning the reserved IP address to the requesting network device. Often, the DCHP server may reserve the IP address for use by the requesting network device for a fixed, often long, duration of time. This “lease,” as the reservation may commonly be referred, may extend for hours or possibly days, assuring the requesting network device of a pseudo-static IP address.
However, if, for some reason, the requesting network device is replaced with a different network device, the DHCP server may be unable to identify the replacement network device and, therefore, unable to reassign the lease with the requesting network device to the replacement network device. As a result, the replacement network device may request an address from the DHCP server, whereupon the DHCP server may reserve another IP address different from the IP address assigned to the replaced network device and assign the new other IP address to the replacement network device. The DHCP server may assign the new IP address without releasing the lease of the previous IP address to the replaced network device. In this respect, the DHCP server may inefficiently maintain the lease for the replaced network device even though this replaced network device no longer operates within the computer network.
Moreover, in some instances, the network employs a number of DHCP relay devices and/or DHCP relay-proxy devices that each relay the DHCP request and response messages between the network devices and the DHCP server across various intermediate sub-networks positioned intermediate to the network devices and the DHCP server. Commonly, each of these DHCP relay devices and/or DHCP relay-proxy devices stores data defining bindings identifying the IP address allocated to the various network devices. In these instances, one or more of these DHCP relay devices and/or DHCP server may be unable to detect that the original network device is no longer present in the network and update its data to remove the binding identifying the IP address allocated to the original network device. Consequently, the DHCP server and these other DHCP relay devices and/or DHCP relay-proxy devices may maintain bindings that are out of synchronization with those stored by the DHCP relay device or DHCP relay-proxy device located in the same sub-network as the original network device.